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From: Nicolas Saenz Julienne <nsaenzju@redhat.com>
To: mingo@redhat.com, peterz@infradead.org, frederic@kernel.org,
	rostedt@goodmis.org
Cc: tglx@linutronix.de, mtosatti@redhat.com, bristot@redhat.com,
	linux-kernel@vger.kernel.org,
	Nicolas Saenz Julienne <nsaenzju@redhat.com>
Subject: [PATCH v2 1/2] sched/isolation: use raw_smp_processor_id() in housekeeping_any_cpu()
Date: Tue,  1 Mar 2022 12:30:52 +0100	[thread overview]
Message-ID: <20220301113053.141514-1-nsaenzju@redhat.com> (raw)

housekeeping_any_cpu() will return a housekeeping CPU. That's it. It'll
try to optimize for NUMA locality and to use the local CPU, but it's not
a requisite.

So let's use raw_smp_processor_id() instead of its vanilla counterpart
in order to allow users to query for housekeeping CPUs without having to
disable preemption.

Signed-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
---
 include/linux/sched/isolation.h | 2 +-
 kernel/sched/isolation.c        | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index 8c15abd67aed..0c09ff1e4599 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -31,7 +31,7 @@ extern void __init housekeeping_init(void);
 
 static inline int housekeeping_any_cpu(enum hk_type type)
 {
-	return smp_processor_id();
+	return raw_smp_processor_id();
 }
 
 static inline const struct cpumask *housekeeping_cpumask(enum hk_type type)
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index b4d10815c45a..c2c1f6d8bb5f 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -43,14 +43,14 @@ int housekeeping_any_cpu(enum hk_type type)
 
 	if (static_branch_unlikely(&housekeeping_overridden)) {
 		if (housekeeping.flags & BIT(type)) {
-			cpu = sched_numa_find_closest(housekeeping.cpumasks[type], smp_processor_id());
+			cpu = sched_numa_find_closest(housekeeping.cpumasks[type], raw_smp_processor_id());
 			if (cpu < nr_cpu_ids)
 				return cpu;
 
 			return cpumask_any_and(housekeeping.cpumasks[type], cpu_online_mask);
 		}
 	}
-	return smp_processor_id();
+	return raw_smp_processor_id();
 }
 EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
 
-- 
2.35.1


             reply	other threads:[~2022-03-01 11:31 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-01 11:30 Nicolas Saenz Julienne [this message]
2022-03-01 11:30 ` [PATCH v2 2/2] tracing: Avoid isolated CPUs when queueing fsnotify irqwork Nicolas Saenz Julienne
2022-03-01 18:58   ` Daniel Bristot de Oliveira
2022-03-01 15:10 ` [PATCH v2 1/2] sched/isolation: use raw_smp_processor_id() in housekeeping_any_cpu() Steven Rostedt
2022-03-01 18:57 ` Daniel Bristot de Oliveira

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